No abstract

A subcutaneous pouch model was developed and used for examination of cellular events in the local acute inflammatory response in the chicken. The model involved insertion of a pair of coverslips-dipped in the irritant-into the prepared subcutaneous pouch, and their replacement with plain coverslips at frequent intervals. The model was simple to operate, caused minimal distress to the experimental bird, and permitted multiple continual sampling of emigrating cells. The cytological features and migratory sequence of inflammatory cells produced by non-immunological and immunological stimuli were studied over a period of 48 h. The initial migration of leukocytes comprised heterophils and monocytes. This was soon followed by emigration of basophils. The basophilic reaction was pronounced in response to Escherichia coli endotoxin. Lymphocytes were prominent in the later stages. Also, in the later stages the monocytes apparently coalesced, formed syncytia and even what appeared to be distinct multinucleated giant cells. The results obtained by the present model corroborated the findings of earlier investigators recorded through the use of tissue sections and impression smears. It is suggested that the subcutaneous pouch model may offer an excellent system in avian inflammation research.

AbstmctBovine spongiform encephalopathy (BSE) or 'mad cow disease' is a new disease with an elusive transmissible agent. However; a 'Prion protein' (PrP) of about 2712 Dalton has been observed to play an essential role in the pathgenecity of BSE. Friesian cattle of 3 -6 years of age have been found susceptible. Common symptoms include weight loss, unmanageable behuviour, traumatic damage due to locomotor deficits and prolonged recumbency. Recent studies suggest that amino acid substitutions in PrP may modulate the development of p&n diseases. Histopathology of brain stem grey matter showed moderate number of discrete ovoid and spherical vacuoles in the neuropil causing spongiform change. The electron microsmpic detection of abnormal fibrils called scrapie-associated fibrils' in the extracts of affected brain may be used as an additional diagnostic ceiterion. lhnsmission has been suspected due to feeding of offals meal, meat meal and bone meal of diseased animals Susceptibility of BSE is probably inherited. However, extensive investigations are required for the establishment of aetwlogy, transmission, pathogenicity and zoonotic potential of BSE, a new nervous disorder of bovines.